(1) Field of the Invention
The present invention relates to a method for transfer voltage adjustment for use in a copier, multifunctional machine, printer, facsimile machine or the like as well as to an image forming apparatus using this method.
(2) Description of the Prior Art
When image forming with toner is carried out in an image forming apparatus such as a copier, multifunctional machine, printer, facsimile machine or the like, in order to keep the image density on recording media that are continuously output constant, optimal transfer conditions for keeping the amount of adhering toner on the toner image support constant are demanded.
Particularly, in a color image forming apparatus, the demanded transfer conditions are prone to change, and if the system setup deviates from the optimal transfer conditions, there occur the problems that the transfer efficiency lowers and that the quality of the output image is affected.
To deal with this, in a conventional art, in order to keep the amount of adhering toner onto the toner image support constant, a plurality of toner patches (reference patterns) are formed so that the optimal transfer conditions are set up by detecting the toner density of these patterns (see patent document 1: Japanese Patent Application Laid-open No. 2000-321832). In detecting the toner density by use of toner patches, the more the number of toner patches, the more exactly the transfer conditions can be determined.
However, when the number of toner patches is increased, there is the problem that an extra amount of toner is consumed other than that used for normal image output.